Wang Qikang, 38, was travelling on the subway when he reached out, touching the naked thigh of a woman standing next to his seat.

She didn’t report it at the time because she wasn’t sure who had touched her. But a video filmed by passengers shows Qikang quickly stroking her bare leg, before turning back to his phone, as though nothing has happened.

According to China.Org.cn, he told the police that he touched the woman accidentally while sleeping – even though his eyes are clearly open in the footage.

Since the video was put online, the former party official has been fired from his travel agency job at the state-owned Jinjiang Shanghai Travel Agency. He also claims that he, and his wife, are receiving abusive phone calls at home.

Online detectives

He was only exposed after passengers – who filmed the footage but seemingly didn’t speak to Qikang, or the girl, during the incident – posted the video onto weibo.com. Outraged users then tracked Qikang down after an extensive online search.

Qikang’s boss was then said to have taken him down to the police station, where he was put under administrative detention.

Qikang touching the woman's thigh

Police said he had been drinking when he twice touched the woman’s thigh, on June 29.

Atranslated videoof the incident shows the men filming it discussing what to do when Qikang touches the woman’s thigh.

“Don’t move,” says the first man, after Qikang touches his victim. “Let’s keep watching.” His companion points out: “Why should we keep on watching?” He replies: “This girl… go there and ask the girl to come and sit here. Be a gentleman.”

Not just in China...

Similar assaults happen here in the UK too. In October last year, Telegraph women's editor, Emma Barnett, was sitting on the bus when a man thrust his hand towards his crotch andstroked her hand.

At first, she was too stunned to do anything, but when she began shouting at him, her husband stepped in and threw the man off the bus.

She was travelling on the Tube when a man came up behind her and ejaculated onto her leg. Chen sprang into action and grabbed her attacker. He was later found guilty in court and added to the Sex Offenders Notice.

At the time Chen told Telegraph Wonder Women: “The one thing we should take from this is to act when we witness these things. Just get your butt to court so these cases don’t get thrown out.”

Filming such incidents and posting them on social media might work in some cases. But, as Chen's case shows, there's no substitute for direct action.